The present invention relates to a process for the production of 6-aminocapronitrile (ACN) and/or hexamethylenediamine (HMD) by a process in which 3-pentenenitrile (3-PN) is hydroformylated to produce a hydroformylation reaction product which contains a mixture of isomers of formylvaleronitrile, isolating the mixture of isomers from the hydroformylation reaction product, and then reductively aminating the mixture of FVN isomers to produce a reductive amination reaction product which contains ACN and/or HMD, either or both of which can be isolated by fractional distillation.
German Patent Application 19631521 discloses a process in which at least one of 2-, 3-, and 4-pentenenitrile is reacted with carbon monoxide and hydrogen in the presence of a catalyst containing at least one Group VIII metal to produce a mixture containing 5-FVN, 4-FVN, and 3-FVN. 5-FVN is first isolated from the mixture and then reacted with ammonia and hydrogen in the presence of a catalyst that contains at least one Group VIII metal to produce ACN and/or HMD. The application discloses the use of distillation as a preferred means of separating 5-FVN from the mixture of 5-FVN, 4-FVN, and 3-FVN.
German Patent Application 19631522 discloses a process for the preparation of ACN and/or HMD by reacting 5-FVN with ammonia and hydrogen in the presence of a catalyst selected from the group consisting of metals or metal compounds of rhenium, copper and elements of Group VIII.
The purification of 5-FVN by fractional distillation from a mixture of 3-, 4-, and 5-formylvaleronitriles can be difficult, due to the instability of the formyl, i.e. aldehyde, group and the level of vacuum necessary to separate and purify the 5-FVN. The instability of the aldehyde group can lead to a loss of FVN due to aldol condensation, and the high vacuum needed for the distillation is impracticable commercially. There is need, therefore, for a process for making HMD and/or ACN in a manner that minimizes 5-FVN loss from aldol condensation, and avoids the need for low pressure fractional distillation to separate 5-FVN from a mixture of 3-, 4-, and 5-formylvaleronitriles.